％The phase locked loop(PLL),adjusts the phase of a local OSCillator
％w.r.t the incoming modulated signal.In this way,the phase of the
％incoming signal is locked and the signal is demodulated.This scheme
％is used in PM and FM as well.
％We will implement it by using a closed loop system.Control systems
％techniques are applied here.
The MAX2870 ultra-wideband phase-locked loop (PLL) and voltagecontrol OSCillator (VCO) can operate in both integer-N and fractional-Nmodes, similar to the Analog Devices ADF4350 wideband synthesizer.This application note compares the MAX2870 and ADF4350 registers andloop filter design in detail. Users who already familiar with ADF4350 canuse this application note as a quick design reference.
Abstract: Many industrial/scientific/medical (ISM) band radio frequency (RF) products use crystal OSCillators to generate areference for the phase-locked loop (PLL)-based local OSCillator (LO). This tutorial provides a basic description of theISM-RF Crystal Calculator, which can be used to calculate various impacts on crystal frequency accuracy and startupmargin for such an LO.
Telecommunication, satellite links and set-top boxes allrequire tuning a high frequency OSCillator. The actualtuning element is a varactor diode, a 2-terminal device thatchanges capacitance as a function of reverse bias voltage.1 The OSCillator is part of a frequency synthesizingloop, as detailed in Figure 1. A phase locked loop (PLL)compares a divided down representation of the OSCillatorwith a frequency reference. The PLL’s output is levelshifted to provide the high voltage necessary to bias thevaractor, which closes a feedback loop by voltage tuningthe OSCillator. This loop forces the voltage controlledOSCillator (VCO) to operate at a frequency determined bythe frequency reference and the divider’s division ratio.
